Becoming Satan's Son
by Criket the Huntress
Summary: Rin finally broke and joined Satan after Satan threatened Shiemi. Now that Satan has Rin, he's teaching Rin how to act like a demon. Rated T for language and violence. Based of a roleplay.
1. Chapter 1

Hi ^^ this is my third story. Its based of a roleplay. I was Rin. It was fun to roleplay. and yeah  
>I don't own Blue Exorcist, I'm not making any money from this all rights belong to the creator.<br>Please R&R Thanks  
>Edit: I realised that I didn't explain how Satan got there XD<p>

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><p>Rin was heading back to his dorm room and noticed a blue light coming from a bathroom. Rin set his stuff down and headed for the bathroom. When he opened the door his eyes widened, Satan possessed one of the students. The student was bleeding from her face and blue flames surrounded her. Rin didn't know the girl, but she seemed strong enough to have Satan possess her long enough. To Rin this was an opportunity to challange Satan.<p>

Rin approached Satan, "Hello father," he said smirking

Satan smiled to his son as he said, "Hello my son."

"You remember that night when you killed Shiro and said I was weak?" Rin asked.

"I remember, have you decided to come to me to become strong?"

Rin laughed "I don't need you to become stronger. I've come to challenge you."

It was Satan's turn to laugh and did he ever. Tears fell from his eyes and he looked to his son. He pointed as he said, "Challenge me? You have a sence of humor my boy."

"Laugh all you want old man." Rin unseathed his sword "I'll show you that I'm not weak."

Satan looked at Rin and shook his head. "You can light the wick of two candles, good for you. Come back when you can do this." Satan had a piece of Rin's own flame slowly eat at his shirt.

Rin put his sword away. "Fine then Satan. But I do have a question for you."

"I may have an answer then," Satan said

Rin looked up to Satan. "What would happen if I did come with you? Not saying that I will or anything, I just want to know."

"You would be taught how to use your flames truly and not have it capped like those exorcist's are doing," Satan answered. "After you learn that then maybe we can work something out with each other. For example, I can get you that girl you want."

Rin thought for a minute. "And what good can come from this, Satan? Will I be used as a weapon?"

"That would be up to you. I am not like Mephisto. I only to have my most powerful son at my side," Satan smiled.

Rin sighed. "What the hell am I thinking?" Rin said quietly. "What will happen to the humans if I go with you?"

"They will fear you, that I can't change. When I grow board again I will create another Blue Night. Whether or not you kill them will be up to you," Satan promised

Rin started to walk away, "I'd much rather not be feared."

"Your going to be feared any way. Isn't it true that your friend Bon hates me for what I did to his temple? What would happen if he found out your my son?" Satan asked. "I can promise you that girl though."

Rin laughed, "he won't find out, I'll make sure of it. Also the girl isn't worth losing everything else. She won't love be because she wants to, it'll be because she has to."

Satan smiled as he said, "He will and as for Shiemi, I have something that I found out watching humans for milliana's. Its a little trick that will have her fall head over heals for you because she wants to."

"How would you know he will? I'm getting better at controlling myself around them. What is this 'trick'?" Rin asked in curiosity.

"All secrets will be found out in the end. As for the trick, well-" Satan placed his finger on his lips and smiled.

"I'll make sure this one isn't found out." Rin glared, wondering what Satan was thinking.

Satan shrugged and sighed. "Your lost. Maybe I'll tell Amaimon then, I'm sure Shiemi can keep him entertained for a while," Satan thought out loud.

Rins glared again. "Leave Shiemi alone!"

"Oh, did I hit a soft spot. I think Shiemi could keep Amaimon happy for a few years before she brakes don't you?" Satan laughed. "Or maybe you want her."

Rin let out a growl "You lay a finger on her and I will kill you."

"You can't lay a finger on me even if you wanted too! Besides, if it's that tamer's wish to be with your elder brother then who are we to get in their way?"

Rin clenches his fists. "She wouldn't fall for someone like him. For all I know this little 'trick' for yours is like some sort of mind control, she'll only be a puppet."

Satan sighed and mocked shocked his head. "Of course you won't believe me, but just watch as she's sweep off her feet. I wonder how many times Amaimon will use this trick to keep her at his side."

Rin smirked "I might not be able to defeat you yet, but I'm sure as hell I can take on Amaimon. Leave Shiemi alone."

"No. This might be fun," Satan smirked

"I swear to God, Satan!" Rin grit his teeth.

"Swear to your God all you want! He can't stop us," Satan laughed

Unable to calm himself down, his flames flared up "I won't let him take her!"

Satan laughed at the flames and said, "If your that pissed off I will teach you the trick. First though you have to join me. Being feared isn't bad Rin. How can it be bad when your own brother fears you?"

"It's not worth it!" Rin yelled

Satan shrugged and grabbed the cell phone is son gave him. "Now which one is Amaimon. It was stupid of me to put their different names in here," Satan lied.

"S-stop!" Rin looked down, feeling defeated "I-I'll come with you.. Just leave Shiemi alone." Rin already regrets his decision

Satan looked up from his phone and smiled. "Let us be on our way then," he said as he put the phone away. He broke three of his fingers and opened the Gate to Gehenna. "Just step in. Once you do I will disband my thoughts of getting Amaimon and Shiemi together."

Rin hesitated for a minute. "you'll leave Shiemi alone?" Rin sighed and entered Gehenna

Satan smiled and followed his son to Gehenna. Once they entered there he quickly lead him to his palace. It was purely black and it was covered in thorns. Demons ran around, torturing humans that hung on the walls. Every now and then a human would fall from the walls and run but the demon's would chase it down with hot pokers. "Welcome to your new home," Satan laughed manically.

Rin looked in disgust at the hanging humans, "this is awful." He said to himself. "Is it just as bad in the inside as is on the outside?"

"The outside would be worse in your opinion," Satan said as he lead him down a hallway. "I love hearing the human's scream but I don't like to have my house too "filled".

He opened one door to a room that looks somewhat normal. "This will be your room. I have other matters to continue to." With that, Satan left.

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><p>AN: This is going to be a pretty long story, I'm still roleplaying it. New chapter up soon.


	2. Chapter 2

Rin walked to the bed an placed his sword by it. "This was a bad idea.." Rin laid down and fell asleep. Two hours later Satan come for his son. He knocked on the door as he walked in. "Rin, its time," he smiled.

Rin sat up on the bed. "Time for what?" He asked sleepily.

Satan grabbed Rin's sword and unsheathed it as he said, "It's time for you to train."

Rin's flames flared up "Fine." Rin got up and followed Satan Satan lead his to a room filled with humans. He pointed to each human as he said, "Your too burn her clothes off, his hair, her shoes, his arm, his eyes, her tunge, her right eye, her left leg, and her toes."

Rin's eyes widened. "Your going to make me hurt innocent people!"

"You think that these are innocent people?" Satan laughed. "Rin, how do human's get here?"

Rin thought for a moment, then it hit him. These people were in Gehenna. "They aren't innocent after all." Rin did what he was told He started with lady and set her shirt on fire, it slowly at her clothes. "Is this like a Punishment?" Rin asked and moved on the next human.

"In a way. All there humans here are here for being possessed by a demon," Satan explained. He nodded as the flame ate the woman's shirt.

Rin set the man's hair on fire. When the man screamed Rin flinched "I'm sorry." Rin mouthed the words to the man. "What will happen to these people when I finish?" Rin set the woman's shoes on fire then the man next to her arm on fire.

"They will be sent to the frozen side of Gehenna to chip ice," Satan said. He slapped Rin's back and ordered, "Don't feel anything for them."

Rin grunted when he was hit on the back. "S-sorry.."

Rin finished up with the humans a few minutes later. "Done.. Now what?"

Satan smiled at Rin's handy work and nodded. He seethed the sword and handed it to a demon made out of shadows. "Now you'll eat and rest. We'll work on your combat fighting later. Follow that demon to the dinning room." He then left and nodded. The demon looked to it's master

Rin glances at the shadowy figure. "Can I not have my sword with me?" Rin followed Satan to the dinning room. "What do you serve here? Death and despair" Rin said jokingly, hoping Satan won't scold him.

Satan ignored Rin jokes and a bowl of soup was placed in front of Rin. "Your only to get your sword when I say. Now eat," Satan commanded.

Rin sighed and looked down at his soup. It didn't look to bad, and the smell wasn't horrible "Hmm this isn't so bad.. If the food is good I might learn to like it here" Rin tasted the soup.

"Good. Its the only food you will find here. After each training you will eat one bowl of human soup, for breakfest you'll have a some bread and demon's tongue. For lunch you can make yourself stuff and for Dinner you'll have whatever the cook feels so," Satan explained.

Rin looked disgusted at the sound of 'Demon tongue.' "Demon tongue? That sounds disgusting." Rin finished up the soup.

Satan shrugged. "We don't have normal meat so we use meat we take from humans and demons. For example, in that soup was made purely from a human child."

"Oh my god!" Rin gagged "Why didn't you tell me that before! Oh god!"

"Because you wouldn't eat it then," Satan said. "Here you eat what is placed in front of you or don't at all."

"I-I'll keep that in mind" Rin is in complete shock that he ate human child soup. "Can't you get like demons out to get you human world meat?" Rin asked.

"We do that only on special occasions. You need to learn that demon food can also be good," Satan said.

"This is going to take a while to get used to.." Rin is already missing his human food

"Come now," Satan commanded as he began to leave the room.

Rin got out of his chair and pushed it back in place then followed Satan. "Now what are we doing?"

"We're going to go to the library I have here," Satan said. They entered a room that was no small book collection. The room was filled with books. Satan looked around and tossed Rin some books as he read the titles, "Latin for beginners, basic torture, human history-Japan version, demonogly...Hmmm, what else?"

"I get to learn torture?" Rin wasn't so fond of the idea.

"Is a basic that all my son's learn. You don't have to use it really," Satan said as he passed him a chess book.

"Chess?" Rin looked at the book.

"Why not. Maybe you can beat Mephisto," Satan said as he gave Rin a demon cook book.

Rin flips through the cook book. "This is weird." Rin closed the book and placed it on the growing pile of other books.

"Also a book about exorcists," Satan said as he placed the book on Rin's pile. "Learn what to stay away from."

Stares at the pile "This is a lot of reading." He complained.

"You have two weeks. If your as smart as Mephisto then you'll be able to finish it then," Satan yawned. "I'll leave you to study."

"What? Two weeks! How the hell am I supposed to read all this is two weeks!" Rin looked sadly down and the books. "Might as well get started now." Rin pinned his bangs out of his face

The shadow demon had followed Satan and Rin to the library. It held Rin's sword and looked to him.

Rin looked at the shadow demon then went back to studying.

The shadow demon looked to the book and took the one Rin was reading.

Rin growled. "Hey, I was reading that!"

The demon looked to Rin and held the book upside down.

Rin held his hand out. "Can I have it back?" He asked the demon.

The demon looked to Rin and back to the book. It opened it's mouth and ate it.

Rin growled and his flames flared up. "WHAT THE HELL?"

The demon stuck out it's black tongue as it reached for another book.

Rin growled louder and grabs the book before the demon gets to it. "No! Bad! You eat another one I'll kill you!"

The demon looked to Rin and nodded. Instead it ate Rin's sword.

"OH HELL NO!" Rin got up and tackled the demon down. "GIVE IT BACK!" Flames got bigger.

The Astro turned into a bat and flew high out of Rin's reach.

Rin yelled. "Fuck my life!"

The bat looked at Rin and got closer. It sensed it did something bad.

Rin stared at the bat, "come to eat anything else important?" Rin sat down, knowing that yelling at the damn thing won't bring his sword or book back.

The bat stayed there for a bit and then flew close to Rin but not too close. It transformed back and looked at Rin.

Rin glanced at the demon. "What do you want?" Rin picked up another book and started to read "Maybe it'll give it back if I'm patient" Rin thought to himself as he read from the book.

The demon came closer and jumped on Rin's back. It looked at the book as if reading.

Rin jumped when the demon got on his back. "GEH! What are you doing!" Rin tried to shake the demon off.

The demon jumped down and hung it's head.

Rin looked at the demon. "You can stay if you are quiet.."

The demon looked to Rin and nodded. It jumped back on Rin's back and transformed into a scarf.

Rin laughed, "Can you transform into anything?" He asked then turned the page of the Human history book.

The Astro saw a flag in the book and transformed into a mini one on Rin

Rin laughed again. "That's a bit distracting".

The astro transformed into a sign that said, "Distracting!"

Rin slammed his head on the book. "By quiet I meant by don't do anything".

The astro stiffened and fell. Not doing anything.

"Oh shit! You can breath and walk around, just nothing distracting! I really need to learn how to say things." Rin went back to his studies

The Astro turned back to it's normal form and stared at Rin.

Rin tried to not notice the Astor but he can feel it staring at him, which freaked him out.

The Astro poked his master

Rin looked at the Astro. "What is it? I'm trying to study."

The Astro opened it mouth and pointed to it.

Rin looked confused. "Are you hungry?"

The Astro nodded like crazy

"Well what do you want?" Rin aksed.

The Astro looked through the cookbook and pointed to a picture of cookies.

"You want those? Okay." Rin got up. "Lets see if the cook is willing to make them." Rin grabbed the Astro's hand and leaves the library. "I'm not sure where the kitchen is..." Rin looked around, since he's new he doesn't know where everything is yet. "A map would be nice."

The Astro stretched and twisted into a map of Satan's castle.

"You are awesome!" Rin held he map and looked for the kitchen. "Its just down the hall." ~Rin walked till he found the door of the kitchen and knocked.

The cook was the same demon Rin met when he tried cooking in the dorm. It looked up to Rin

"Oh hey! Its you. I have a question. Will you be willing to make these?" Rin showed him the cookies that the Astro wanted.

The demon nodded and made a batch of the cookies. It handed the cookies to Rin.

"Thank you" Rin nodded to the demon. "Okay Astro, mind if I call you that? Here you go." gives him the cookies.

Astro grabbed the plate and shook them in its mouth. He left one cookie alone. Astro looked to Rin and pulled one of the books out and gave it to its master.

"Oh? Thank you." Rin took the Latin book from Astro. "Before we go back to the library, is there anything else you want?"

Astro thought for a moment and shook its head.

"Okay" Rin led the way back to the library and opened the door for Astro. "hmm more studying..." Rin sat down and opened his Latin book and started to take notes.

Astro looked at the book and changed it's shape to the words.

Rin looked at Astro "Want me to read from you instead?" Rin said as he put his pen down.

Astro transformed into hands and clapped. It then transform into a word

Rin blinked "You know it would be faster if you turned into a giant book." He laughed.

Astro did as he was told and transformed into a book three times the size of the one Rin had. It opened and the words where white but all it said was "Cookies are good"

Rin shook his head. "Close but not quite." Rin opened his book to show Astro what he meant. Like the words in this book. "If you can do that, I'll have Ukobach make you more of those cookies."

Astro got excited and copied the words in the book

Rin smiled and picked up Astro. "Thanks Astro." Rin flipped through the pages of the book. A few hours passed and Rin started to get a headache. "Ugh! That's enough reading. You can go back to your normal form if you want."

Astro transformed back and looked to Rin. It looked around and sighed

Lets go get your cookies.

Astro turned into a hand and punched the air. It transformed into a bat and zoomed to the kitchen

Rin ran after Astro. "hey, wait up." They arrived to the kitchen to find Ekobach in the kitchen. "I have another order of those cookies, mind making them again. Last time tonight I swear."

The kitchen demon nodded and made another batch. This time he made a little more and Astro spun in circles above Rin's head.

Rin bowed to the kitchen demon ."Lets go to bed Astro." With the plate in hand Rin led Astro out. "Crap, I forgot where my room was. Astro would you mind helping?"

Astro transformed into a map again. He eyed the plate of cookies

Rin picked up Astro and made his way to the room. "You can have these when we get to the room." Rin wandered around a bit before finding his room. When he got to his room, Rin tried to open the door but was shocked. "Ow! Oh yeah the code. Seccondo Evvie E." Rin opened the door.

Astro took the plate from Rin and hid under his bed and started to eat the cookies.

Rin places the books down on a wooden desk and changed out of his clothes. then he plops down on his bed. "Night Astro." Shortly after Rin drifted off.

Astro looked up from his hiding spot. He went to the books and he hacked up the last book he took before. He wiped the crumbs off before he went to Rin's bed and fell asleep at his feet.

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><p>AN: Here's chapter two. Rin is living with Satan and he made a new friend, even though his new friend is a pain in the butt -.-  
>Chapter three might be up today or tomorrow. Thanks for the reviews!<p> 


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